On Sat, Feb 12, 2000 at 06:04:04PM +0800, Steve Underwood wrote:
> Karen Shaeffer wrote:
>
> > On Fri, Feb 11, 2000 at 11:24:12AM -0800, Larry McVoy wrote:
> OK. Now we seem to have seen some oversimplification and some overcomplication. I
> think reality lies somewhere between.
>
> Most of the complexity referred to by Karen lies in the back end of the drive. The
> front end is more flexible. It already appears in at least two forms - IDE, SCSI,
> and sometimes some flavour of the month serial interface. I'm not saying IDE and
> SCSI drives have common back ends, but they do use common technology ([OT]
> Actually, I find the level of back end commonality puzzling. It used to be that
> the mechanics of IDE and SCSI drives looked identical and ran that the same speed,
> but everyone said they were totally different, with vastly different reliability.
> Now almost all IDEs all run at 7200RPM, and almost all SCSIs at 10,000RPM and
> people keep telling me the mechanics are now the same. Go figure.) Anyway,
> whatever happens in the murky microworld of the platters and their immediate
> control electronics has little to do with the interface they present to the world.
>
> The critical word in designing the external interface is "cheap". The whole darned
> drive retails for US$100 to 200. The BOM must be much lower than that. A Celeron
> is a non-starter on cost grounds (its fan is comparable to the size of a whole
> disk drive, but a Crusoe wouldn't solve the cost issue). A serial interface,
> whether using Ethernet technology or some other, could add many dollars to the
> BOM, since it needs to run at near GigE speeds. The required additional RAM and
> ROM to support it would also hurt the cost structure.
>
> The bottom line is that despite the exotic technology going into a disk drive's
> back end, its the front end which now most affects it price. I think we are more
> likely so see forms of hot plug IDE trying to displace hot plug SCSI, than any
> form of serially connected disk drive go mainstream - at least in the near future.
>
> Steve
---end quoted text---
I disagree with several of your assertions--but any further discussion is
moot. You have the final word.
-- ---- Karen Shaeffer Neuralscape; (831) 426-8547 Santa Cruz, Ca. 95060 shaeffer@neuralscape.com http://www.neuralscape.com -------------------------------------------------------- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
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